Further exploration of the Verkhnechonskoye field of technical groundwater: new research methods and results

The purpose of the research is to refine a geological model of the Verkhnechonsk field of technical groundwater (Eastern Siberia, Russia), reassess groundwater reserves by the industrial category and form a geofiltration model. The article deals with the main approaches used in conducting of field and desk researches. It also introduces the organization experience of large-scale pilot filtration work under time- and personnel-limited conditions at a large operating field. The work is based on the results of long-term regime observations, field experimental and filtration works carried out in 2019- 2020. It uses the information of a geological database on the water and oil intake facility of wells, including a complex of borehole studies, as well as the data on the geological and hydrogeological structure of the field according to archival and published sources. Visual ModFlow Flex software was used to create a geofiltration model. Having conducted and interpreted the works, the justification of a natural hydrogeological model different from the one adopted earlier was performed. Thus, the relationship of two water-bearing complexes – the Verkholensky-Ilginsky complex of the Upper-Middle Cambrian age and the Litvintsevsky complex of the Lower-Middle Cambrian age was proved. The works in the Visual ModFlow Flex resulted in the creation of a geofiltration model, which correlates well with the actual data, allows to identify impenetrable barriers, as well as predicts the geomigration of hydrogen sulfide. It is the first time that the underground water reserves of the field were included in the State balance sheet in full-scale according to the industrial category B. The reassessment was performed for three sites of the field, well loads were adjusted for optimal operation of water intakes. The obtained results of the conducted research imply that the use of geofiltration model is reasonable in the fields of complex geological structure and this model can be used on a permanent basis for monitoring and adjusting of the development mode. The organization experience of works at a large operating oil field can also be useful under the reserve reassessment at analogous fields.

1. Tkachuk V. G. Hydrogeology of the USSR. In 50 vol. Vol. 19. Irkutsk region. Moscow: Nedra; 1968. 496 p. (In Russ.)

2. Blokhin Yu. I. Formation features of fresh groundwater in terms of the geological structure of the Lena oil-bearing area. In: Materialy IV soveshchaniya po podzemnym vodam Sibiri i Dal'nego Vostoka = Materials of the 4th meeting on groundwater of Siberia and the Far East. Irkutsk –Vladivostok; 1964, p. 102–103. (In Russ.).

3. Blokhin Yu. I. Natural resources of fresh groundwater in the small basins of the upper Lena river. In: Materialy V soveshchaniya po podzemnym vodam Sibiri i Dal'nego Vostoka = Materials of the 5th meeting on the groundwater of Siberia and the Far East. Irkutsk – Tyumen; 1967, p. 213–214. (In Russ.).

4. Blokhin Yu. I. Types of small basins of the upper Lena region. In: Geologiya i poleznye iskopaemye Vostochnoi Sibiri = Geology and minerals of Eastern Siberia. Irkutsk; 1971, p. 103–107. (In Russ.).

5. Zamaraev S. M. Tectonic structure and history of geological development of the Southeastern part of the Siberian platform. In: Geofizicheskie issledovaniya i problemy neftegazonosnosti yuga Sibirskoi platform = Geophysical research and issues of the oil and gas potential in the south of the Siberian Platform. Iss. 2. Moscow: Gostoptekhizdat; 1962, p. 128–193. (In Russ.).

6. Leshchikov F. N. Frozen rocks of the Angara and Baikal region. Novosibirsk: Nauka; 1978. 141 p. (In Russ.).

7. Lomonosov I. S., Kustov Yu. I., Pinneker E. V. Mineral waters of the Baikal region. Irkutsk: Vostochno-Sibirskoe knizhnoe izdatel'stvo; 1977. 223 p. (In Russ.).

8. Pinneker E. V. Brines of the Angara-Lena Artesian basin: distribution patterns, composition, dynamics, formation and use. Moscow: Nauka; 1966. 332 p. (In Russ.).

9. Pinneker E. V., Pisarskii B. I. Underground waters of the Baikal-Amur Mainline zone. Novosibirsk: Nauka; 1977. 85 p. (In Russ.).

10. Malkov D. S. Hydrogeological conditions for oiland-gas-content of the Verkhnechonskoye gas-condensate-oil field. Geo-Sibir'. 2010;2(1):18-21. (In Russ.).

11. Shenkman B. M. Free water exchange zone of Verkhnechonskoye oil-gas-condensate deposit in the early stage of the industrial operation. Izvestiya Irkutskogo gosudarstvennogo universiteta. Seriya: Nauki o Zemle = The Bulletin of Irkutsk State University. Series: Earth Sciences. 2014;7:129-144. (In Russ.).

12. Shenkman B. M. Groundwater resources of the Verkhnechonskoye oil and gas condensate field. Geografiya i prirodnye resursy. 2013;3:77-84. (In Russ.).

13. Shenkman B. M. The groundwater chemistry of Verkhnechonskoye oil-gas-condensate deposit (VCHOGCD). Izvestiya Irkutskogo gosudarstvennogo universiteta. Seriya: Nauki o Zemle = The Bulletin of Irkutsk State University. Series: Earth Sciences. 2013;6(1):206-222. (In Russ.).

14. Grinbaum I. I. Geophysical methods to determine filtration properties of rocks. Moscow: Nedra; 1965. 188 p. (In Russ.).

15. Gershanovich I. M. Hydrogeological studies in wells by the flowmetry method. Moscow: Nedra; 1981. 295 p. (In Russ.).

16. Aksenovskaya A. A., Valeev R. R., Grinchenko V. A., Savelyev E. A. Determination of hydrodynamic parameters on the result of testing for groundwater inflow and geofiltration simulation by the example of Srednebotuobinshy technical groundwater deposit. Nedropol'zovanie XXI vek. 2020;5:63-69. (In Russ.).

17. Moskovtseva D. A., Kichigin E. V. Geofiltration modeling and characterization of the Lebedinsky underground water. Geologiya, geografiya i global'naya energiya = Geology, geography and global energy. 2021;2:68-73. (In Russ.). https://doi.org/10.21672/2077-6322-2021-81-2-068-073.

18. Samartsev V. N. Estimation of aquifer heterogeneity with automatic model calibration. Inzhenernye izyskaniya = Engineering Survey. 2013;12:32-39. (In Russ.).

19. Grinevskiy S. O., Ivanova Y. V., Safonov A. O. An assessment of the groundwater resources based on infiltration recharge hydrogeological modeling. Izvestiya vysshikh uchebnykh zavedenii. Geologiya i razvedka = Proceedings of higher educational establishments. Geology and Exploration. 2016;5:45-52. (In Russ.). https://doi.org/10.32454/0016-7762-2016-5-45-52.

20. Roshal A. A., Potapova E. Y. Hydrodynamic and migration modeling at an assessment of stocks of underground waters (on an example of the Moscow region). Nedropol'zovanie XXI vek. 2012;2:70-75. (In Russ.).